A grommet is fit externally to a wire harness to be wired in a vehicle and mounted in a through hole of a vehicle-body panel. The grommet has a small-diameter cylindrical portion molded of elastomer and through which the wire harness is tightly inserted. A radial projection in the form of bellows projects radially out from an outer peripheral position of an intermediate longitudinal part of the small-diameter portion. An outer peripheral portion is connected to the outer peripheral end of the radial projection. The outer peripheral portion has a conical tubular shape and is connected at an intermediate longitudinal position to the radial projection. An annular vehicle-body locking recess is provided on the outer peripheral surface of a large-diameter side of the outer peripheral portion. A small-diameter side is thicker than the radial projection portion.